Twitter Streamin API crash

require 'rubygems'
require 'em-http'
require 'json'
require 'mysql'

class LanguageDetector
  URL = "http://www.google.com/uds/GlangDetect"

  include EM::Deferrable

  def initialize(text)
    request = EM::HttpRequest.new(URL).get({
      :query => {:v => "1.0", :q => text}
    })

    # This is called if the request completes successfully (whatever the code)
    request.callback {
      if request.response_header.status == 200
        info = JSON.parse(request.response)["responseData"]
        if info['isReliable']
          self.succeed(info['language'])
        else
          self.fail("Language could not be reliably determined")
        end
      else
        self.fail("Call to fetch language failed")
      end
    }

    # This is called if the request totally failed
    request.errback {
      self.fail("Error making API call")
    }
  end
end

# connect to the MySQL server
dbh = Mysql.real_connect("localhost", "MyUser", "MyPass", "MyDB")

EM.run {
  username = 'MyTwitterUsername'
  password = 'MyTwitterPassword'
  buffer = ""

  http = EventMachine::HttpRequest.new('http://stream.twitter.com/1/statuses/sample.json').post({
    :head => { 'Authorization' => [ username, password ] }
  })

  http.callback {
    unless http.response_header.status == 200
      puts "Call failed with response code #{http.response_header.status}"
    end
  }

  http.stream do |chunk|
    buffer += chunk
    while line = buffer.slice!(/.+\r\n/)
	if line!=nil
	      tweet = JSON.parse(line)
	      if (tweet['user']['screen_name']!=nil && tweet['text']!=nil)
     			puts tweet['user']['screen_name'] + ": " + tweet['text']
	      end
	end
    end
  end
}